[PATCH v1 3/4] qemu_domain.c: do not launch ppc64 guests with 'pmu' setting

[Andrea Bolognani]

On Tue, 2020-03-24 at 11:05 -0300, Daniel Henrique Barboza wrote:
> On 3/24/20 11:00 AM, Andrea Bolognani wrote:
> > On Tue, 2020-03-24 at 09:27 -0300, Daniel Henrique Barboza wrote:
> > > For the sake of completeness, I'll also mention that we can simply allow <pmu/> to be
> > > declared in the XML, handling the <pmu state='on'/> inside the QEMU driver to not add the
> > > bogus '.pmu' parameter for QEMU ppc64, forbid <pmu state='off'/> to be declared, and
> > > nothing else. No auto-generation of XML indicating that the guest will support a PMU.
> > 
> > Looking again at how other architectures, specifically x86 and ARM,
> > handle this, the PMU is generally enabled by default without this
> > fact being reflected in the domain XML; the user can then go ahead
> > and specifically ask for it to be turned on or off, at which point
> > libvirt will add the relevant bits to the QEMU command line.
> > 
> > This is basically the second behavior you're describing above, and
> > I think it would be perfectly fine if that's the one we would adopt
> > for ppc64.
> 
> I guess I'll roll with this one then. I will allow <pmu state='on'/> to be
> declared in the XML without breaking QEMU. For <pmu state='off'/> I'll
> throw an CONFIG_UNSUPPORTED error mentioning that PMU can't be turned off
> for ppc64.

Sounds good.

-- 
Andrea Bolognani / Red Hat / Virtualization